#
# Examples of aspect graph's computation on freeform surfaces.
#
#					Gershon Elber, Nov. 2002
#

save_res = resolution;

resolution = 60;

ComputeParabolicLines = function( s ):
    return = sparabolc( s, true ):
    adwidth( return, 2 ):
    awidth( return, 0.01 ):
    attrib( return, "gray", 0.5 ):
    attrib( return, "rgb", "100,255,255" );

ComputeTopoAspectGraph = function( s, Spc ): ag: sp: s1:
    ag = saspctgrph( s ):
    color( ag, yellow ):
    adwidth( ag, 3 ):

    sp = sphereSrf( 1 ):
    color( sp, red ):

    s1 = s * tx( 0 ):
    color( s1, green ):
    adwidth( s1, 2 ):

    return = list( list( ag, sp, axes ) * sc( 0.6 ) * tx( Spc ),
		   list( s1, axes ) * tx( -Spc ) );

#############################################################################

c = cbspline( 4,
	      list( ctlpt( E2, 0,    0.15 ),
		    ctlpt( E2, 0.25, 0.15 ),
		    ctlpt( E2, 0.52, 0.4 ),
		    ctlpt( E2, 0.85, 0.3 ),
		    ctlpt( E2, 0.85, 0.0 ) ),
	      list( kv_open ) );
c = -c + c * sx( -1 );

srfEight = surfprev( c * ry( 90 ) );
color( srfEight, yellow );
awidth( srfEight, 0.001 );

SParabs = ComputeParabolicLines( srfEight );
interact( list( srfEight, SParabs ) );

#
# View the aspect graph with silhouettes...
#
SAspect = ComputeTopoAspectGraph( srfEight, 0.9 );

viewstate("PolyAprx", 1);
viewstate("PolyAprx", 1);
viewstate("NumIsos", 0);
viewstate("NumIsos", 0);
viewstate("NumIsos", 0);
viewstate("NumIsos", 0);
viewstate("LowResRatio", 1);
viewstate("LowResRatio", 1);
viewstate("DSrfSilh", 1);

interact( SAspect );

save( "aspct1gr", SAspect );

viewstate("DSrfSilh", 0);
viewstate("PolyAprx", 0);
viewstate("PolyAprx", 0);
viewstate("NumIsos", 1);
viewstate("NumIsos", 1);
viewstate("NumIsos", 1);
viewstate("LowResRatio", 0);
viewstate("LowResRatio", 0);

free( srfEight );

#############################################################################

c = pcircle( vector( 0, 0, 0 ), 1 );

srf8b = -sFromCrvs( list( c * sc( 0.001 ),
		         c * sc( 1 ),
		         c * sc( 1 ) * tz( 1 ),
		         c * ry( -20 ) * sc( 0.6 ) * sx( 0.2 ) * tx( 0.4 ) * tz( 0.4 ),
		         c * ry( -20 ) * sc( 0.2 ) * tx( -0.4 ) * tz( 1.7 ),
     		         c * sc( 0.65 ) * tz( 2 ),
     		         c * sc( 0.65 ) * tz( 3 ),
     		         c * sc( 0.001 ) * tz( 3 ) ),
	       4, kv_open );
color( srf8b, yellow );
awidth( srf8b, 0.001 );

resolution = 40;

SParabs = ComputeParabolicLines( srf8b );
interact( list( srf8b, SParabs ) );

#
# View the aspect graph with silhouettes...
#
SAspect = ComputeTopoAspectGraph( srf8b, 0.9 );

viewstate("PolyAprx", 1);
viewstate("PolyAprx", 1);
viewstate("NumIsos", 0);
viewstate("NumIsos", 0);
viewstate("NumIsos", 0);
viewstate("NumIsos", 0);
viewstate("LowResRatio", 1);
viewstate("LowResRatio", 1);
viewstate("DSrfSilh", 1);

interact( SAspect );

save( "aspct2gr", SAspect );

viewstate("DSrfSilh", 0);
viewstate("PolyAprx", 0);
viewstate("PolyAprx", 0);
viewstate("NumIsos", 1);
viewstate("NumIsos", 1);
viewstate("NumIsos", 1);
viewstate("LowResRatio", 0);
viewstate("LowResRatio", 0);

free( srf8b );

#############################################################################

resolution = save_res;

free( c );
free( SParabs );
free( SAspect );